1. Field of the Invention
The present invention relates to a dental reamer which tapers right down to its tip, of the type including helical slits which, on their sides, have cutting lips for boring out dental canals, in which the characteristics of the cutting conditions are defined by, on the one hand, a cutting angle .alpha. determined by the tangent to the cutting edge at the cutting point and the perpendicular to the surface to be cut at this point and, on the other hand, a clearance angle .beta. determined by the plane of the cutting surface and the tangent to the inactive face of the cutting edge.
The angles .alpha. and .beta. will be defined more precisely below.
2. Description of the Related Art
In a boring process using a reamer of the type described above, a compromise must be found between the values of the angles .alpha. and .beta., which may assume positive or negative values, independently of one another. Depending on the values which are chosen, the results may range from a lack of cutting efficiency, which will need to be compensated for by very strong cutting forces, to a very strong cutting force which will entail a risk of screwing the rotating instrument. As is known, the screwing effect can be eliminated by the presence of a heel on the periphery of the instrument, albeit with the drawback of further increasing the cutting forces and therefore the risk of the instrument being broken.